linux-kernel - Re: [PATCH] cpufreq: cpufreq-dt: Restore default cpumask

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Message-ID: <20141027152251.0249368b@free-electrons.com>
Date:	Mon, 27 Oct 2014 15:22:51 +0100
From:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To:	Geert Uytterhoeven <geert+renesas@...der.be>
Cc:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	linux-pm@...r.kernel.org, linux-sh@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: cpufreq-dt: Restore default
 cpumask_setall(policy->cpus)

Dear Geert Uytterhoeven,

On Mon, 27 Oct 2014 14:44:40 +0100, Geert Uytterhoeven wrote:
> Commit 34e5a5273d6aa0ee ("cpufreq: cpufreq-dt: extend with
> platform_data") changed cpufreq_init() to only call
> cpumask_setall(policy->cpus) if the platform data indicates that all
> CPUs share the same clock. Before, cpufreq_generic_init() did this
> unconditionally.
> 
> This causes a crash on r8a7791/koelsch when resuming from s2ram:
> 
>     Enabling non-boot CPUs ...
>     CPU1: Booted secondary processor
>     Unable to handle kernel NULL pointer dereference at virtual address 0000003c
>     pgd = ee71f980
>     [0000003c] *pgd=6eeb6003, *pmd=6e0e9003, *pte=00000000
>     Internal error: Oops: a07 [#1] SMP ARM
>     Modules linked in:
>     CPU: 0 PID: 1397 Comm: s2ram Tainted: G        W      3.18.0-rc2-koelsch-00762-g7eed2a4e61d2d978 #581
>     task: ee6b76c0 ti: ee7f0000 task.ti: ee7f0000
>     PC is at __cpufreq_add_dev.isra.24+0x24c/0x77c
>     LR is at __cpufreq_add_dev.isra.24+0x244/0x77c
>     pc : [<c029e084>]    lr : [<c029e07c>]    psr: 60000153
>     sp : ee7f1d48  ip : ee7f1d48  fp : ee7f1d84
>     r10: c04e8448  r9 : 00000000  r8 : 00000001
>     r7 : c054a8c4  r6 : 00000001  r5 : 00000001  r4 : 00000000
>     r3 : 00000000  r2 : 00000000  r1 : 20000153  r0 : c054a950
>     Flags: nZCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment user
>     Control: 30c5307d  Table: 6e71f980  DAC: fffffffd
>     Process s2ram (pid: 1397, stack limit = 0xee7f0240)
> 
>     ...
> 
>     Backtrace:
>     [<c029de38>] (__cpufreq_add_dev.isra.24) from [<c029e620>] (cpufreq_cpu_callback+0x6c/0x74)
>      r10:eec75240 r9:c04e8448 r8:c04ef3a0 r7:00000001 r6:00000012 r5:00000000
>      r4:00000012
>     [<c029e5b4>] (cpufreq_cpu_callback) from [<c003f20c>] (notifier_call_chain+0x48/0x70)
>      r4:ffffffdd r3:c029e5b4
>     [<c003f1c4>] (notifier_call_chain) from [<c003f2cc>] (__raw_notifier_call_chain+0x1c/0x24)
>      r8:00000001 r7:00000010 r6:00000000 r5:00000000 r4:00000012 r3:ffffffff
>     [<c003f2b0>] (__raw_notifier_call_chain) from [<c0026a00>] (__cpu_notify+0x34/0x50)
>     [<c00269cc>] (__cpu_notify) from [<c0026a34>] (cpu_notify+0x18/0x1c)
>      r4:00000001
>     [<c0026a1c>] (cpu_notify) from [<c0026c44>] (_cpu_up+0x108/0x144)
>     [<c0026b3c>] (_cpu_up) from [<c0381c68>] (enable_nonboot_cpus+0x68/0xb8)
>      r10:00000000 r9:c04e8ee6 r8:00000000 r7:00000003 r6:c04e8528 r5:c0506248
>      r4:00000001
>     [<c0381c00>] (enable_nonboot_cpus) from [<c0059038>] (suspend_devices_and_enter+0x29c/0x3e8)
>      r6:c0506e70 r5:00000000 r4:00000000 r3:60000153
> 
> Restore the old default of calling cpumask_setall(policy->cpus) if no
> platform data is available to fix this.
> 
> Fixes: 34e5a5273d6aa0ee ("cpufreq: cpufreq-dt: extend with
> platform_data")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> ---
>  drivers/cpufreq/cpufreq-dt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index 2f25958053778ad1..3bfc1175a548c49c 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -293,7 +293,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
>  	policy->cpuinfo.transition_latency = transition_latency;
>  
>  	pd = cpufreq_get_driver_data();
> -	if (pd && !pd->independent_clocks)
> +	if (!pd || !pd->independent_clocks)
>  		cpumask_setall(policy->cpus);
>  
>  	of_node_put(np);

Aah, yes, indeed.

Reviewed-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>

Thanks for spotting the issue and fixing it!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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